Gray Treefrog(Hyla versicolor)

Other names: tetraploid gray treefrog

The gray treefrog, as its Latin name suggests, has the chameleon-like ability to change its colour.

Characteristics

The gray treefrog has “warty” green, brown or grey skin with large darker blotches on the back. Like many treefrogs, this species has large suction-cup-like toe pads. It has a white patch under each eye and is bright yellow-orange under the thighs. Adults may reach a length of six centimetres. The call of this species is a short flute-like trill. Listen to the call of gray treefrog (courtesy of Adopt-A-Pond Wetland Conservation Programme).

Similar Species

Toads are similarly warty but are almost always various shades of brown, and lack the toe pads characteristic of the gray treefrog. Toads also have large parotoid glands behind the eyes.

Habitat

The gray treefrog may be found in many types of tree and shrub communities located near permanent water. The species usually lives in woodlands but may also frequent orchards. The gray treefrog is a true “tree frog”: it can be found at the top of even the tallest trees. These frogs are rarely seen outside the breeding season. When they are not active, they hide in tree holes, under bark, in rotten logs, and under leaves and tree roots. Gray treefrogs overwinter under leaf litter and snow cover. Their eggs and larvae develop in shallow woodland ponds and marshes, puddles, ponds in forest clearings, swamps, bogs and many other kinds of permanent or temporary waterbodies that have no significant current, including ponds that humans have excavated.

To view an interactive map of the known ranges of gray treefrogs in Ontario, click here.

Biology

Gray treefrogs breed in late spring and early summer. They, like various other frog species, tolerate freezing temperatures. During the day, these frogs remain in trees around the breeding pond. In the evening, males call from trees and shrubs but enter the pond after finding a mate. The females lay up to 2,000 eggs in small clusters of 10 to 40, which are attached to vegetation. The eggs hatch within five to seven days, and the tadpoles metamorphose between 40 and 60 days after hatching.

The gray treefrog is a tetraploid form of the Cope’s gray treefrog, Hyla chrysoscelis – in other words, genetically the same as the Cope’s gray treefrog – but has four copies of each chromosome instead of the usual two copies. Gray treefrogs are sometimes seen on the outside walls or windows of buildings where a light attracts insects. The skin of these frogs provides excellent camouflage against bark and lichens.

Threats & Trends

Treefrogs depend on forests. Therefore, habitat loss and degradation due to clearcutting, roads, agriculture and urbanization are the main threats to these frogs. Their tendency to remain in trees, coupled with excellent camouflage, probably serve as effective defences against predation. The very limited data available about this species indicates that it is probably present in fairly large numbers, despite substantial habitat loss throughout its range.